Food products, such as grains, rice, flour, peanuts, sugar, and the like are typically transported in bulk by rail cars, trucks, and other similar transportation means, with rail car transport being one of the most-often used methods. Commonly found in such stored food products are insects, larvae, and eggs which are often introduced into the products during transport. The infestation which often occurs to these types of products is particularly severe in the summer months, though such infestation occurs in the winter months as well. In recognition of the infestation which commonly occurs with the aforementioned types of food products during transport, it is well known to treat the food products with various types of pesticides during transport to kill the insects, larvae, and eggs therewithin. One pesticide which is typically utilized to treat the stored food products is aluminum phosphide which is sold under the tradename PHOSTOXIN. Typically, the pesticides are applied to the stored food products as a fumigant or in a block form which is interposed in the container vessel.
Recently, various medical studies have concluded that the pesticides currently utilized to treat the aforementioned food products during transport give rise to various health risks upon long-term exposure or contamination. In this respect, studies conducted at the University of Minnesota, Laboratory of Environmental Medicine and Pathology, have found that an elevated incidence of chromosomal aberrations occurs in blood lymphocytes of male rats exposed to 3 ppm and higher concentrations of phosphene. These studies have also found that phosphene attacks DNA in humans causing chromosome aberrations. In recognition of the health risks associated with such chemicals, those individuals involved in the loading and unloading of the aforementioned types of products from rail cars and other container vessels are often required to wear protective gear and breathing apparatus to prevent exposure to the high levels of the chemicals present in the container environment. With regard to the rail car transport of these products, recent legislation which has been enacted to mitigate some of the health risks associated with the unloading of the rail cars requires that the rail cars be vented during transport immediately prior to the unloading thereof. Such legislation also requires that people in the vicinity of the area where the rail cars are vented be alerted that the venting is occurring.
As an alternative to the utilization of chemical pesticides to treat the stored food products during transport, it has been found that lowering the oxygen level within the transport container vessel to 5% or less and maintaining this level for extended periods of time has a toxic effect on the insects, larvae, and eggs found in the products. It has also been shown that a small percentage of carbon dioxide in combination with a low oxygen level can decrease the kill time, thereby increasing the effectiveness of the low oxygen levels within the container vessel. The present invention recognizes the health risks associated with the use of pesticides by providing a replacement for such pesticides in the form of a system utilizing nitrogen-generating membranes to create an atmosphere within the transport container vessel not exceeding a 5% oxygen level.